Process and apparatus for producing metal plates with integral stiffeners



Dec. l0, 1968 A, R. BRINGEWALD 3,415,095

PROCESS AND APPARATUS FOR PRODUCING METAL PLATES WITH INTEGRAL STIFFENERS fg /5 INVENTOIL /5 E n 4am/sr 5PM/@Mw Dec. l0, 1968 A. R. BRlNGEwALD 3,415,095

PROCESS AND APPARATUS FOR PRODUCING METAL PLATES WITH INTEGRAL STIFFENERS Filed Feb. i, 1967 5 Sheets-Sheet 2 T.; 4 INVENTOR.

,406057 F. e/wfa/Aw Dec. l0, 1968 A. R. BRINGEWALD 3,415,095

PROCESS AND APPARATUS FOR PRODUCIN ETAL PLATES WITH INTEGRAL STIFFENE Fild Feb. 8, 1967 5 SheeT'S-Sheet 5 I N VE N TOR. ,4am/57K 5km/65nm@ United States Patent O 3 415,095 PROCESS AND APPARATUS FOR PRODUCING METAL PLATES WITH INTEGRAL STIFFENERS August R. Bringewald, Huntington, N.Y., assignor to Bringewald Process Corporation, Huntington, N.Y. Filed Feb. 8, 1967, Ser. No. 614,702 8 Claims. (Cl. 72--192) ABSTRACT OF THE DISCLOSURE Rolling mill techniques are applied to blanks of aluminum or other materials by loading a blank on the upper Sculptured face of a die that is located in a novel form of container, having a flexibly supported frame, which container definitely prevents the flow of material under rolling mill pressure outside the container by confining the material to a space constituting a pressure chamber, composed of a traveling portion defined by the upper Sculptured face of the die and the projecting upper edge of the container frame, and stationary closures on both feeding ends of the rolling mill, thereby forcing the material to follow the path of least resistance by filling the cavities of the die and producing the desired part and avoiding waste of material.

Although any high power impact or constant pressure equipment may be adapted to facilitate the new process, modied standard rolling mill equipment is considered the rnost efcient equipment to execute the present invention.

CROSS REFERENCES This application is related to the inventions of my applications Ser. No. 383,011, filed July 16, 1964, and Ser. No. 438,204, filed Mar. 9, 1965, both now abandoned in favor of my continuation-in-part application, Ser. No. 613,896, filed Feb. 3, 1967.

Background of the invention Prior to this and my related inventions, large skins for airplane wings having integral stiffeners arranged cordwise and/or span-wise or skins for missile bodies having integral stiffeners, arranged in any pattern, have been machined out of solid bar stock of huge dimensions on chip removing machines in very time-consuming processes, because there has been no other process available to produce these structural members in a more economical way. Machining these parts out of solid material is not only a very time-consuming but also a materialwasting process. Chip material of 75% to 85% of the original blank material is more often the rule rather than the exception.

Referring to the familiar contour rolling or roll forging process, efforts have been made to produce integrally stiffened parts by subjecting a blank of material, placed on the Sculptured face of a die and both together on a movable bed, to the forces of a rolling mill. Like in rolling sheet stock, the material is not restrained but can move freely in its horizontal plane as it is squeezed between the die and roll. Following the path of least resistance, the material is partially extruded into the relatively wide and shallow cavities of the Sculptured die face and partially wasted by extruding it out in rolling direction ahead of the die as the die passes under the roll. The result is the production of parts showing only a modest extrusion effect and a high percentage of material wasted.

Since the horizontal compression forces in rolling direction, induced into the material by the vertical cornpression forces of the upper roll, are so tremendous, not even the provision of dams at the ends of the die in rolling direction can prevent the undesired ow of material.

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In this case the material upsets, buckles and overflows the dams. The result again in a poor extrusion effect and Waste of material.

Summary of the invention The present invention proposes to overcome the foregoing as well as other problems in the fabrication of integrally stiffened construction members, especially of large parts requiring relatively thin and high stiffening elements. To this end and in accordance with the present invention, a rolling mill of conventional design is modied by adding a unit, consisting of a roll bed and an adjustable pressure control body on each feeding end of the rolling mill. A novel form of container is loaded with a die, and a blank of process material placed on the upper face of the die which is Sculptured to facilitate the extrusion of a desired part. The container comprises a bottom plate and a frame which is supported flexibly around the edge of the bottom plate. The upper edge of the frame projects above the die, thereby surrounding the process material at a height of approximately the thickness of the same in order to restrain the material and prevent it from any plastic flow in its horizontal plane during processing. The Sculptured face of the die together with the projecting edge of the container frame constitutes the traveling p0rtion of a pressure chamber. The closure on top of the pressure chamber is provided by the two stationary adjustable pressure control bodies under which the traveling portion of the pressure chamber reciprocates.

To extrude a part, the container with its contents is fed between the rolls of the rolling mill. During the entire cycle of the extrusion process, the container with its contents not only passes between the rolls of the rolling mill, but also between the roll beds and their respective pressure control units which are adjusted to induce auxiliary pressure into the blank in order to control the flow of material and prevent undesired material distribution.

Under the pressure of the upper roll of the rolling mill, the flexibly supported container frame retracts and adjusts itself in accordance with the reduction in thickness of the blank. The plastic flow of the material, developed by the high compression forces of the upper roll, is confined to the previously described pressure chamber. In this pressure chamber the displaced material, resulting from the reduction in thickness of the blank, is trapped and forced to follow the path of least resistance by progressively filling the cavities of the entire sculptured face of the die as the container with its contents advances between the rolls of the rolling mill to produce the desired part.

Brief description of the drawings FIG. l is partly a side elevational section and partly a sectional View on line 1-1 of FIG. 2 showing the arrangement of the main components in the initial position of processing a part.

FIG. 2 is a fragmentary cross-section on line 2-2 of FIG. l showing the relation of the main components during proces ing of a part.

FIG. 3 is a fragmentary cross-sectional view on the line 3-3 of FIG. l showing the relation of the main cornponcnts ready for processing a part.

FIG. 4 is a sectional plan view taken. on the line 4--4 of FIG. 5, with part of the blank material broken away to reveal a portion of the die.

FIG. 5 is a sectional elevation on the line 5 5 of FIG. 3 showing the position of the exibly supported container frame tilted under the impact of the upper roll It also shows the arrangement of the gear and :rack and the coupling of the container with the rack.

FIG. 6 is a perspective View of a part produced in accordance with the present invention.

Description of the preferred embodiments The equipment for carrying out the process of my invention comprises generally the rolling mill with its upper adjustable roll 11 and lower roll 12 and a container 13. Gears 15 are xedly supported on two necks adjacent to the ends of the lower roll 12, and racks are provided to coact with gears 15 for feeding the container 13, prepared for processing and coupled with racks 20 by bolts 22 (FIG. 3), between the upper roll 11 and lower roll 12. The rolling mill 10 includes roll beds 25 and pressure control bodies 35 on the feeding ends of rolling mill 10. Each of the two roll beds 25 supports four cylinders 31 in which oil or air pressure actuates pistons 32 with their piston rods 33. The four respective piston rods of each roll bed 25 support a pressure control body 35 to which the piston rods are secured by bolts 36. The two pressure control bodies 35 may be adjusted separately to the required independent pressures by applying pressure as required to the respective sets of four cylinders. These pressures may be synchronized with the movements of the container 13 for the purposes mentioned below.

Also as a part of this invention, an enclosure 60 constituting a sealed chamber 61 is provided. The purpose of the two pressure control bodies 35 and the sealed chamber will be hereinafter described.

The inner ends 68 (FIG. 5) of the pressure control bodies 35 are shaped to prevent their interference with the upper roll 11 and to provide freedom of movement for said pressure control bodies 35 in order to enable the clost ing of any gap which could occur between their inner ends 68 and the upper roll 11 for the purpose of preventing material tlashing and material escape.

To reduce the friction between the process material and the pressure control bodies during processing, the pressure control bodies may comprise rolls 67 as indicated in FIG. 5.

The container 13, adapted to receive a die 40, the spacers 52 (FIG. 3) and the process material 44, comprises a bottom plate 41 which has a stepped down recess around its outer edge to hold the elastic pad 42. The elastic pad 42 supports the container frame 62 flexibly to enable said frame to retract and to adjust itself under the pressure of the upper roll 11 while the container 13 with its contents passes between said upper roll and lower roll 12 for processing. One end of the container frame 62 is provided at both sides with holes 46 (FIG. 3) to receive bolts 22 (FIGS. 3 and 6) for coupling the container with the racks 20.

To produce an integrally stiifened part in accordance with the present invention, the die 40, having its upper face Sculptured to extrude a desired part, is loaded in the container 13 and a blank of process material 44 placed on said die in the space provided by the upper face of the die and the projecting edge of the flexibly supported container frame 62 which surrounds the die 40. Expandable spacers 52 are placed between the longitiudinal beams of the container frame and process material for the purpose explained below. To prevent material waste, the volume of the process material is to be held within close tolerances of the volume of the finished part.

The loaded container 13, best shown in FIG. l, has a certain initial height which determines the adjustment of the upper roll 11 to an opening between the upper roll and lower roll 12 best suited for the desired extrusion results. The container 13 with its contents is placed on the roll bed 25 in the space provided by said roll bed and preszure body 35, and coupled with racks 20 by bolts 22. The gears 15, fastened to the necks of the lower roll 127 have a pitch diameter which coincides with the outer diameter of the body of the lower roll 12, and are adapted to coact with the racks 20 for the purpose of feeding the container 13 with its contents between the upper roll 11 and lowerl roll 12 at a speed identical with the circumferential speed of the outer diameter of the lower roll 12.

Before processing a part, the pressure control bodies 35 are vertically adjusted by actuating the respective pistons 32 with the piston rods 33 to provide the upper stationary closures for the traveling portion of the pressure chamber 63 in which the extrusion process takes place. The pressure chamber 63 is formed by the Sculptured upper face of die 40 and the projecting edge of the ilexibly supported container frame 62 with its expandable spacers 52 and, depending on the processing position of container 13, by the pressure control bodies 35.

The purpose of the pressure control bodies 35 is twofold: rst, to provide the upper stationary closures for the traveling part of the pressure chamber 63 as described above and, second, to induce auxiliary pressure into the process material as will be seen.

By actuating the upper roll 11 and lower roll 12 in counter rotating direction, as indicated by arrows in FIGS. l and 5, the racks 20, coacting with the gears 15 of the lower pressure roll 12, feed the container 13 with its contents between said rolls. As the container 13 with its contents advances between the upper roll 11 and lower roll 12 the entire area of the process material 44 is incrementally subjected to the full pressure of the upper roll 11 resulting in a most eifective extrusion impact per area unit.

The horizontal compression forces, induced into the process material 44 -by the vertical compression forces of the upper roll 11, could cause non-uniform plastic flow of the process material in rolling direction and gather material at an increasing rate toward the trailing end of the container. To counteract this undesired flow of material, the pressure control bodies 35 are adjusted to induce auxiliary pressure of a predetermined magnitude into the leading and trailing portions of the process material 44 for the duration of the process cycle.

The process material 44 together with elastic pads 42 gives way to the pressure of the upper pressure roll 11, and the exibly supported container frame 62 retracts and thereby adjusts the pressure chamber 63 in height in accordance with the reduction in thickness of said process material. The spacers 52, made from steel or other material of higher mechanical properties than the process material, maintain their upper edge level with the changing upper face of the advancing process material and, acting like dams, seal the constantly changing gaps 64 that occur during processing between the upper edge 65 of the container frame 62 and the lower faces 66 of the pressure control bodies 35 to prevent lateral material escape.

The process material 44, trapped in the pressure chamber 63, yields to the pressure exerted by the upper roll 11 by reducing its thickness in accordance with the roll setting. Following the path of least resistance, the excess material, controlled by the auxiliary pressure of the pressure control bodies 35, is extruded into the cavities of the die 40 thereby producing the desired part.

Enclosure 60, constituting a processing chamber, is tightly sealed for the purpose of purging said chamber with inert gases, like helium or argon, for processing titanium, beryllium or other materials susceptible to atmospheric contamination when heated above the critical susceptive temperature.

It should be understood that the structure and the procedure described are illustrative of apparatus and process for carrying out this invention and that variations may be made by those skilled in this art without departing from the spirit of the invention and that only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. Apparatus for extruding material from a ductile workpiece to form an article of more complex contour than the workpiece, comprising:

(a) rolling mill means including:

(1) opposed upper and lower roll means;

(2) a pair of support means aligned with the opposite sides of the lower roll means for supporting material approaching and leaving the roll means; and

(b) a die contoured on its upper face with the reverse form of one side of the article to be formed;

wherein the improvement comprises:

(c) a bottom plate for supporting said die with the workpiece resting on the contoured upper face of the die;

(d) a vertically compressible frame on said plate encircling the die and workpiece and extending at least as high as the upper surface of the workpiece throughout its periphery; and

(e) means for driving the assembled frame, die and workpiece along the support means and between the upper and lower roll means.

2. Apparatus as delined in claim 1, including a pair of pressure control mechanisms, one spaced above each of said support means, for engaging the upper surface of the frame and workpiece outside of the opposed roll means and cooperating at times with its associated support means to compress the frame and the workpiece.

3. Apparatus as defined in claim 2, in which each of said pressure control mechanisms comprises a plate having a ilat under surface adapted to engage the top surface of the frame.

4. Apparatus as defined in claim 2, in which each of said pressure control mechanisms comprises a plurality of parallel rolls adapted to engage the top surface of the frame.

5. Apparatus as defined in claim 2, comprising a pair of spacers extending along the sides of the frame between the frame and the workpiece, said spacers being deformable to maintain a seal between the frame below and the upper roll means and pressure control mechanisms above, to prevent lateral escape of metal from the workpiece.

6. The method of extruding material from a ductile workpiece to form an article of more complex contour than the workpiece, comprising the steps of (a) assembling the workpiece with a die to dene the contour of a surface of the finished article;

(b) moving the die and workpiece between a pair of opposed upper and lower roll means to compress the workpiece;

wherein the improvement comprises:

(c) assembling the workpiece with the die lby placing the workpiece on the upper surface of the die, within a vertically compressible frame extending at least as high as the upper surface of the workpiece; and

(d) compressing the frame ybetween the roll means so that the roll pressure is transferred to the workpiece and forces the material thereof into recesses in the die.

7. The method of claim 6, comprising the further step of maintaining pressure on the surfaces of the workpiece which are not between the opposed roll means.

8. The method of claim 6, comprising the further step of providing deformable spacers along the sides of the workpiece to inhibit lateral escape of material from the workpiece.

References Cited UNITED STATES PATENTS 543,607 7/1895 Bates 72-1'84 1,967,788 7/ 1934 Seiferth 72-207 2,988,838 6/1961 Morgan 72-184 FOREIGN PATENTS 1,039,016 9/ 1958 Germany.

CHARLES W. LANHAM, Primary Examiner. L. A. LARSON, Assistant Examiner.

U.S. Cl. XR. 72-207, 363, 465 

